Sabermetric Special- Ultimate Zone Rating (UZR)

There is one aspect of baseball that fans might only notice four or five times a game. Fielding. I say that fans notice it four or five times a game because fans are much more likely to observe and (most importantly) remember either a good play made by a fielder, or an error. Errors and good fielding happens four or five times a game. 

Well, like everything to sabermetrics, there is a stat dedicated to defense. Sabermetricians use the Ultimate Zone Rating (UZR), a statistic comparing the event that actually happened (hit/out/error) to data on similarly hit balls that have been hit in the past to determine how much better or worse the field did than the “average player.” It’s a much more complicated version than Defensive Runs Saved (DRS), but is a little more accurate. Remember my post on Wins Above Replacement? UZR is kind of like WAR, but is dedicated to good fielding. A high UZR does positively correlate with a high defensive WAR stat. 

Like WAR, UZR has a long and complicated equation to calculate it. Instead of an equation, here are four big components to UZR (these are sabermetrics too, and are all components of UZR):

Double-Play Runs (DPR) – The amount of runs above average an infielder is in turning double-plays.

Error Runs (ErrR) – Notices if a player commits more or fewer errors than the league average at their position.

Range Runs- Sees if a player gets more balls in a game than the league average or not (this also depends on position too). 

Outfield Arm Runs (ARM) – For outfielders, of course. The amount of runs an outfielder saves with their arm by either throwing out someone or preventing runners to advance.

A high UZR would be someone who gets lots of gold gloves, like Greg Maddux, who won 18 Gold Gloves, or Ivan Rodriguez, who won 13 gold gloves. Maddux and Pudge have some of the highest UZR ratings, if not the highest, and are considered one of the best defensive players in their respective positions.

UZR is broken down kind of like standard deviations. An UZR of 1 means that the player is +1 above from the league average in fielding. 

But remember these things:

·         Watch out for sample sizes: UZR takes time to form, and really isn’t a good stat until a player has spent about 3 years in the Major Leagues. Then you can draw conclusions about if they are the best fielder. If a player only spent 100 innings (11 or 12 games) at a position, that’s not a good sample to draw for UZR (even though for normal statistics a good sample size is more than 30. It’s different for UZR). 

·         UZR is park-adjusted, so watch out for that weird center-field gap in Houston.

·         It’s different from year to year. The fielding average might be a little different from the 1960’s than compared to today. In a five year span, however, it should remain relatively the same, unless it’s a very different year for some reason. 

Check out UZR/150, which scales a player’s defense based on a 150 game basis.

That’s today’s statistic special. Have any questions/comments/concerns? Email me at statsbuddy42@gmail.com

-Evan Boyd